Photographic developer



United States Pateflffi 2,843,483 PHOTUGRAPHIC DEVELOPER Donaid ill.Kridcl, Walter V. Wadman, and Joseph G. Stamptii, Rochester, N. Y.,assigmors to Eastman Kodak Company, Rochester, N. Y., a corporation ofNew Jersey No Drawing. Application October 3, 1955 Serial No. 538,281

s Claims. (31. 96-66) This invention relates to photographic developersand particularly to photographic developer mixtures in dry form withwhich suitable solutions. for the development ofphotographic paper andfilm may be prepared. More particularly the present invention relates toimproved developing compositions containing compounds which willmarkedly lessen the aerial oxidation in developers which are employed toproduce the extreme contrast required in preparinghalf-tone or linenegatives for use known materials which serve to improve the action ofphotographic solutions such as boric. acid and potassium bromide. Watersoluble compounds such as citrates, sulphates and phosphates maylikewise be added in solid condition to restrict the swelling ofgelatin, or thelike. Fog restraining and inhibiting substances maybepresent. V

The components including the developing agent and the aldehyde bisulfitecompound are mixed together in suitable proportions and then'may bepackaged for distribution. The base component is generally not added tothe powder mixture containing the developer since it might accelerateoxidation or deterioration of the developer. Also, the base in thepresence of moisture could cause decomposition of the aldehyde bisulfitesalts with loss of the aldehyde. The base component, therefore, can beincluded in a separate package or may be added to the developingsolution at the time it is prepared.

This developing powder mixture forms the developing solution when addedto water in the presence of a base.

The base reacts with the aldehyde-sulfite compound causing it todecompose into aldehyde and sulfite. Strong inorganic bases such assodium hydroxide, sodium carbonate, etc, increase the rates of aldehydeformation and are preferred. They are also desirable to employ sincethey provide an increased contrast. Phenol type developers such ashydroquinone, ortho catechol, and chlorhydroquinone may be employed inthe above described developer compositions.

, It has been found, however, that the developers described in theabove-mentioned patent are quite susceptibleto aerial oxidation. Whenthe developer solution is exposed to the air in developing trays itrapidly discolors and loses activity. An increasing developing time is,therefore, required to maintain the desired image density as the aerialoxidation proceeds. This adds an additional variable to a process whichis already critical in respect to other variables.

y The present invention therefore is an improvement over the inventiondescribed, of course, more completely in Patent 2,313,523 than incertain of the foregoing parar Eatented, July 15, 1958 graphs. We havediscovered that if in addition to the bisulfite compounds offormaldehyde mentioned in the patent, small concentrations of sodiumand/ or potassium bisulfite compounds of other carbonyl compounds arepresent, the aeration life of these developers is greatly improved. The.presence of the sodium and/ or potassium bifulfite compounds of acetone,acetaldehyde, aldol, isobutyraldehyde, methyl ethyl ketone, glyoxal,methoxy acetaldehyde is particularly eifective in increasing thisaeration life.

For example, sodium formaldehyde bisulfite has a low dissociationconstant in the type of photographic developer in which it is ordinarilyused. The dissociation constant is a measure of the degree of separationofa compound into its components and in this case is expressed as:

whereK is the dissociation constant, (CS) the concen tration ofdissolved but associated carbonyl bisulfite compound, and (H+), (C), (S)the concentrations of hydrogen ion, carbonyl compound, and sulfiterespeclatter, however, if used alone have a detrimental eifect on thesensitometric properties of the complete developer. However, we-havefound in accordance with the present invention that when theaforementioned carbonyl bisulfite compounds are employed with sodiumformaldehyde bisulfite they will give excellent protection againstoxidatlon without any appreciable effect on the sensitometricproperties. 2

Concentrations of the order of 5 to 15 grams per liter of one or more ofthese additional bisulfite compounds produce an appreciable improvementin stability toward aerial oxidation without appreciably changing thespeed, contrast, or dot quality produced by the initial solutions.

To illustrate the improvement of the present invention over thatdescribed in Patent 2,313,523, developers were prepared in whichformaldehyde sodium bisulfite alone was used and also in which a portionof the formaldehyde bisulfite was replaced by another carbonyl bisulfitecompound, in accordance with the present invention.

They were compared in a test which is often used on this type ofdeveloper, called a tray life test. The respective developer solutionsare poured into individual 12 x 14 inch development trays to a depth ofapproximately /2 inch and allowed to stand 8 hours in a conditioned roomat 72 F. Test strips, which have been exposed identically, are developedunder identical conditions at the start and after 4 an'd8 hoursstanding. The densities of the images on the strips are read on adensitometer from which can be computed the developer speed atsuccessive times and from these the speed loss of the developer onstanding in the open is obtained.

The general'formula for the developers was as follows:

Grams Total carbonyl bisulfite compounds 36.0 Composed of:

Sodium or potassium formaldehyde bisulfite 21.0-36.0 Other carbonylbisulfite 5.0-l5.0 Hydroquinone 22.5 Boric acid 4.0 Sodium carbonate,monohydrate 55.0

Potassium bromide 1.6

formaldehyde bisulfite.

3 The chemicals are dissolved in the order given above in suflicientwater to make 1 liter total volume to form the developer solution.

Example 1 A developer was prepared containing 9.0 grams of sodiumacetone bisulfite and 27.0 grams of sodium formaldehyde bisulfiteinstead of 36.0 grams of the sodium or potassium formaldehyde bisulfitein the above formula.

It showed a speed gain of 12% and 24% after 4 and 8 hours standingrespectively compared with a speed loss of 50% and 83% for theformaldehyde bisulfite alone.

Example 2 7 A developer was'made which contained 9.0 grams of -sodium'isobutyraldehyde bisulfite and 27.0 grams of sodium formaldehydebisulfite instead of the same total of the sodium or potassiumformaldehyde bisulfite. It

: produced a speed gain of 3% after both 4 and 8 hours standing ascompared with a loss of 50% and 83% for the formaldehyde bisulfite.

Example 3 Another developer was prepared with 15.0 grams of :sodiumacetaldehyde bisulfite and 21.0 grams of sodium formaldehyde bisulfitein place of all sodium or potassium The speed loss Was 34% and 59% after4 and 8 hours respectively in comparison to 50% and 83% for straightformaldehyde bisulfitea Example 4 In another developer, 15.0 grams ofsodium methyl ethyl ketone bisulfite and 21.0 grams of sodiumformaldehyde bisulfite was employed instead of all sodium or potassiumformaldehyde bisulfite. There was no speed loss but instead a gain inspeed of 13.0% and 11.4%

after 4 and 8 hours standing.

Example 5 In another developer, 12 grams of sodium glyoxal bisulfite wasused to replace the same weight of sodium formaldehyde bisulfite. Itsspeed loss after 4 and 8 hours was 32 and 60% compared with 50 and 83%for formaldehyde bisulfite alone.

Example 6 In another case, 6 grams of potassium acetone bisulfitereplaced that weight of the sodium or potassium formaldehyde bisulfite.The developer showed a speed gain of 17.7% after 4 hours and a loss of6% after 8 hours instead of losses of 50% and 83% respectively withstraight formaldehyde bisulfite.

Example 8 In another instance, 5 grams of sodium acetone bisulfite weresubstituted for that weight of sodium formaldehyde bisulfite. This timethe resultant developer gained 25% in speed after 4 hours and lost 16.7%after 8 hours instead of the 50% and 83% losses with formaldehydebisulfite.

Our invention therefore has the particular advantage r 4 of preventingaerial oxidation of developer solutions containing sodium or potassiumformaldehyde bisulfite and prevents loss of development speed.

We claim: 1. A photographic developer composition containing an organicsilver halide developer, an alkali, a buffer component, a carbonylbisulfite component consisting of at least one alkali metal carbonylbisulfite selected from thegroup consisting of sodium and potassiumformaldehyde bisulfite and at least one alkali metal carbonyl bisulfiteselected from the group consisting of sodium and potassium carbonylbisulfite compounds having two to six carbon atoms in the molecule andhaving a higher dissociation constant than sodium formaldehydebisulfite.

2. A photographic developer composition containing an organic silverhalide developer, an alkali, a buffer component, an antifoggant, acarbonyl bisulfite component consisting of at least one alkali metalcarbonyl bisulfite selected from the group consisting of sodium andpotassium formaldehyde bisulfite and at least one alkali metal carbonylbisulfite selected from the group consisting of sodium and potassiumcarbonyl bisulfite compounds having two to six carbon atoms in themolecule and having a higher dissociation constant than sodiumformaldehyde bisulfite.

3. A photographic developer composition containing hydroquinone, sodiumcarbonate, boric acid, potassium bromide, a carbonyl bisulfite componentselected from the group consisting of sodium and potassium formaldehydebisulfite and at least one alkali metal carbonyl bisulfite selected fromthe group consisting of sodium and potassium carbonyl bisulfitecompounds having two to six carbon atoms in the molecule and having ahigher dissociation constant than sodium formaldehyde bisulfite.

4. A photographic developer composition containing an organic silverhalide developer, an alkali, a carbonyl bisulfite component consistingof sodium formaldehyde bisulfite and sodium acetonebisulfite, a buffercomponent, and an antifoggant.

5. A photographic developer composition containing an organic silverhalide developer, an alkali, a carbonyl :bisulfite component consistingof sodium formaldehyde bisulfite and sodium isobutyraldehyde bisulfite,a buffer component, and an antifoggant.

6. A photographic developer composition containing an organic silverhalide developer, an alkali, a carbonyl bisulfite component consistingof sodium formaldehyde bisulfite and sodium acetaldehyde bisulfite, abuffer component, and an antifoggant.

7. A photographic developer composition containing an organic silverhalide developer, an alkali, a carbonyl bisulfite component consistingof sodium formaldehyde bisulfite and sodium methyl ethyl ketonebisulfite, a buffer component and an antifoggant.

8. A photographic developer composition containing an organic silverhalide developer, an alkali, a carbonyl bisulfite component consistingof sodium formaldehyde bisulfite and sodium glyoxal bisulfite, a buffercomponent and an antifoggant.

References Cited in the file of this patent UNITED STATES PATENTS707,403 Eichengrun Aug. 19, 1902 2,313,523 Donovan et al. Mar. 9, 1943 I2,458,376 Henn Jan. 4, 1949

1. A PHOTOGRAPHIC DEVELOPER COMPOSITION CONTAINING AN ORGANIC SILVERHALIDE DEVELOPER, AN ALKALI, A BUFFER COMPONENT, A CARBONYL BISULFITECOMPONENT CONSISTING OF AT LEAST ONE ALKALI METAL CARBONYL BISULFITESELECTED FROM THE GROUP CONSISTING OF SODIUM AND POTASSIUM FORMALDEHYDEBISULFITE AND AT LEAST ONE ALKALI METAL CARBONYL BISULFITE SELECTED FROMTHE GROUP CONSISTING OF SODIUM AND POTASSIUM CARBONYL BISULFITECOMPOUNDS HAVING TWO TO SIX CARBON ATOMS IN THE MOLECULE AND HAVING AHIGHER DISSOCIATION CONSTANT THAN SODIUM FORMALDEHYDE BISULFITE.